The chart below provides a graphic representation of Aspect Ratios from 2 to 8, where they intersect ring sizes up to one inch i.d. and wire diameters from 24SWG to 10SWG.
The colored lines are CONSTANT aspect ratios, meaning that any ring ID/Wire diameter combo along that line will look and feel the same in a weave. The left side of the chart (Y axis) represents the inner diameter of a ring, and the bottom (X axis) represents the wire diameter.
All the measurements are shown in decimal inches, but on the X axis, common American and Standard guages are indicated (Also indicated by the dots on the A.R. lines), and on the Y axis, common fractional inch measurements are indicated.
Sorry, no metric. The data visualization package I used only allowed 1 set of values per axis. Later versions may have this, if I can figure it out. However, a rough conversion can be made with the formula MM = Dec.Inch * 26, or conversely, Dec. Inch = MM/26 ....